KR930004775B1 - Three dimensional image pick-up device - Google Patents

Abstract

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Description

[Name of invention]

3D imaging device

[Brief Description of Drawings]

1 is a block diagram showing a schematic configuration of a three-dimensional imaging device according to an embodiment of the present invention.

2A is a schematic configuration diagram of an imaging device used in a three-dimensional imaging device.

2b is an operation timing and a switching timing chart of the liquid crystal shutter.

3A and 3B are timing charts for switching the operation timing of the image pickup device and the liquid crystal shutter.

4A and 4B are operation timing charts when the imaging tube is used for the three-dimensional imaging device.

5 is a block diagram of a conventional three-dimensional imaging device.

6 is a block diagram of an optical shutter.

Detailed description of the invention

[Technical Field]

The present invention relates to a three-dimensional imaging device for three-dimensional imaging of the subject image.

[Background]

Conventionally, as a basic method of three-dimensionally capturing a subject image, the subject image is picked up at an arbitrary angle using two television cameras, and the output signals of the two television cameras are alternately switched for each field. Methods are known. 5 shows a schematic configuration diagram of the above three-dimensional imaging device. In FIG. 5, the A side shown by a dashed-dotted line is a three-dimensional imaging device, and the B side is a three-dimensional display device. In the figure, 1 is a subject, 2 is a television camera A, 3 is a television camera B, and the television cameras A and B have a lens arranged in front of an imaging surface. 4 is a synchronous signal generator, 5 is a switch, 6 is an adder, and the three-dimensional imaging device is comprised by the above. 7 is a synchronous separator, 8 is a monitor television, 9 is glasses, and the three-dimensional display apparatus is comprised by the above.

Since the three-dimensional imaging device and the three-dimensional display device having such a configuration are well known, only a brief description is given here. First, the three-dimensional imaging device will be described. The television camera 2 and the television camera 3 are arranged keeping the arbitrary angle θ with respect to the same subject 1.

In addition, the scanning timings of the television camera 2 and the television camera 3 are kept in synchronization. Therefore, the television camera 2 and the television camera 3 are simultaneously supplied with pulsed signals necessary for driving the television camera from the synchronization signal generator 4 (the television camera 2 and the television camera 3 are each human's own). It corresponds to the right eye and the left eye).

The video output signals of the television camera 2 and the television camera 3 are connected to respective terminals (a) of the switch 5. The switch 5 is controlled by a field pulse supplied from the synchronization signal generator 4, which is an output signal from the terminal (c) of the switch 5, and a video signal obtained from the television camera 2 in the first field. In the second field, video signals obtained from the television camera 3 are alternately obtained for each field. The three-dimensional video signal can be obtained by supplying and adding the switched video signal and the synchronization signal supplied from the synchronization signal generator 4 to the adder 6. Here, it goes without saying that the driving pulses, the field pulses, and the synchronization signals of the television camera output from the synchronization signal generator 4 are all in synchronization.

Next, the three-dimensional display device will be described. The three-dimensional image signal obtained by the three-dimensional image pickup apparatus of the above structure is transmitted to the three-dimensional display apparatus by any means. The transmitted three-dimensional video signal is supplied to and displayed on the monitor television 8. Since the three-dimensional video signal displayed on the monitor television 8 is a signal obtained by alternately switching the video output signals of the television camera 2 and the television camera 3, not only can it be detected as a three-dimensional image, It becomes an unnatural image such as a double view.

When viewing the image displayed on the monitor television 8 as a three-dimensional image, the image captured by the television camera 2 can be seen by the viewer's right eye only, and the image captured by the television camera 3 can be seen by the viewer's left eye only. do. In other words, the image of the first field may be selected so that the image of the first field is incident on the right eye and the image of the second field is incident on the left eye. As a means, using the spectacles 9 having an optical shutter function, the optical signal from the monitor television 8 is selected so that the image of the first field is seen by the right eye and the image of the second field is visible by the left eye. The field pulses synchronized with the synchronous signal are output from the synchronous separator 7. Here, the field pulse output signal from the sync separator 7 is set to the high level in the first field and the low level in the second field. The field pulses are supplied to the spectacles 9 and the optical shutter incorporated in the spectacles 9 is alternately interrupted to select the optical signal from the monitor television 8 as the right eye and the left eye. That is, in the first field, the optical shutter for the right eye of the glasses 9 transmits light, the optical shutter for the left eye blocks the light, and in the second field, the optical shutter for the left eye of the glasses 9 emits light. It transmits, and the optical shutter for the right eye blocks the light. In this way, the optical signal from the monitor television 8 is selected to observe the three-dimensional image.

Next, an outline of the optical shutter will be described. The optical shutter may be a mechanical shutter, but a liquid crystal shutter is used here. The liquid crystal shutters can control light interruption by voltage, have a fast response speed with respect to the field scan frequency of a television camera, and have a longer life and simpler handling than a mechanical shutter.

Hereinafter, the liquid crystal shutter will be briefly described using FIG. 6 is a schematic view of an optical shutter unit. 10 and 11 are deflection plates, 12 are liquid crystals, 13 and 14 transparent electrodes, 15 are square wave generators, 16 and 17 are AND circuits, 20 and 21 are capacitors, 18 are inverters, and 19 are field pulse input terminals. The basic configuration of the optical shutter is to arrange a liquid crystal (twist nematic type) 12 between two types of deflection plates 10 and 11, and apply an electric field to the liquid crystal to form an optical shutter to interrupt the light. have. Since the said twisted nematic liquid crystal is well-known, the description is abbreviate | omitted.

The optical portion of the optical shutters 100 and 200 is composed of a deflection plate, a liquid crystal, and a transparent electrode. The deflection plate 10 transmits only horizontal polarization of light from the subject, the deflection plate 11 transmits only vertical polarization, and the transparent electrode 14 is grounded. The transparent electrode 13 is for applying an electric field to the liquid crystal 12. In the above configuration, when no voltage is applied to the transparent electrode 13, the horizontal polarization transmitted through the deflection plate 10 passes through the liquid crystal layer 12, resulting in abnormal vertical polarization, and thus the liquid crystal layer. The vertical polarization passing through 12 passes through the deflection plate 11. In other words, the liquid crystal shutter is transmitted, and light from the monitor can reach the human eye. On the other hand, when a voltage is applied to the transparent electrode 13, the horizontal polarization transmitted through the deflection plate 10 does not become abnormal even when passing through the liquid crystal layer 12, and maintains the state of the horizontal polarization. For this reason, the horizontal polarization which passed the liquid crystal layer 12 cannot pass through the deflection plate 11. That is, since the liquid crystal shutter is shielded, the light from the monitor cannot reach the human eye. As described above, the transparent electrode 14 is grounded, and a driving signal is supplied to the transparent electrode 13 through the capacitors 20 and 21. The driving voltage applied to the transparent electrode 13 is about 10V and the driving frequency is about 200Hz. The drive signal is generated by the square wave generator 15, the AND circuits 16 and 17, the inverter 18, and the field pulse input terminal 19.

That is, the square wave generator 15 generates a square wave of about 200 Hz, and simultaneously outputs the output signal of the square wave generator 15 to one terminal of the AND circuits 16 and 17. The other terminal of the AND circuit 16 is supplied with a field pulse in which the first field supplied from the field pulse input terminal 19 is high level and the second field is low level. For this reason, the AND circuit 16 outputs the drive signal of the liquid crystal layer only at the first field. On the other hand, since the field pulse supplied from the field pulse input terminal 19 is supplied to the AND circuit 17 as a signal inverted by the inverter 18, the AND circuit 17 only drives the liquid crystal layer during the second field. Is output.

The liquid crystal shutter is constituted by the above structure. That is, in the first field, the right shutter 100 of the glasses 9 shown in FIG. 6 transmits light, and in the second field, the left shutter 200 of the glasses 9 transmits light.

However, the three-dimensional imaging apparatus is expensive because the three-dimensional imaging apparatus according to the above configuration requires two television cameras. In addition, the angle of view, focus, and angle between the subject and the two television cameras must be precisely adjusted when the same subject is captured by two different television cameras. Therefore, much time is needed for adjustment of an apparatus compared with the time to image. In addition, there was a problem such as lack of mobility.

[Initiation of invention]

In view of the above problems, an object of the present invention is to provide a three-dimensional imaging device which is inexpensive and easily adjustable. In order to achieve the above object, the present invention has at least a photoelectric conversion element and a vertical transmission means, and transmits the signal charges accumulated in the respective photoelectric conversion elements to the corresponding vertical transfer stage substantially simultaneously, once in one field. Using a television camera using an image pickup device having a configuration of reading out abnormally, a subject image from two optical path systems is alternately switched for each field, approximately coinciding with the timing of transferring signal charges from the photoelectric conversion element to the vertical transfer stage. The imaging is performed to obtain a three-dimensional image.

According to the above configuration, the subject image of the two optical path systems is alternately selected in synchronization with the field scan of the television image pickup device, and imaged three-dimensionally using a single television camera. At this time, the image pickup device used in the television camera has at least an idle conversion element and a vertical transfer end, but when the photoelectric conversion element is also combined with the vertical transfer end, it has a configuration in which a signal charge storage unit is provided on an extension of the transfer direction of the vertical transfer end. Then, an image pickup device capable of surface scanning is used so as to simultaneously transfer the signal charges accumulated in each photoelectric conversion element to a corresponding vertical transfer stage, so as to simultaneously capture an image of one screen. In addition, the accumulation time of the signal charges to the photoelectric conversion elements of the image pickup device is equal to or less than one field syringe period. The subject image from the two optical path systems incident on the image pickup device is roughly matched to the timing of transferring signal charges from the photoelectric conversion element of the image pickup device to the vertical transfer stage, and is alternately switched from field to field using an optical shutter. Using a television camera equipped with the imaging device described above, the accumulation time of the signal charges of each imaging device to each photoelectric conversion element is equal to or less than one field scanning period, and the switching timing of the optical path system is determined from each photoelectric conversion element of the imaging element. By approximately coinciding with the timing of transmitting the signal charges to the vertical transfer stage, it is possible to capture a three-dimensional image with good image quality using a single television camera.

Best Mode for Carrying Out the Invention

Hereinafter, a first embodiment of a three-dimensional imaging device according to the present invention will be described with reference to the drawings.

In FIG. 1, the side A shown by a dashed-dotted line is a three-dimensional imaging device, and the side B is a three-dimensional display device. 40 is a TV camera, 4 is a synchronization signal generator, 6 is an adder, 22, 23, 26 are mirrors, 24 and 27 are liquid crystal shutters, 25 is a half mirror, 28 is an inverter, 16, 17 is an AND circuit, 15 is a square wave generator. , 20 and 21 are capacitors.

The first optical path system is configured by the mirrors 22, 23, the liquid crystal shutters 24, and the half mirror 25, and the second optical path system is configured by the mirrors 26, the liquid crystal shutters 27, and the half mirrors 25. Consists of. The three-dimensional imaging device is constituted by the synchronization signal generator 4, the adder 6, the mirrors 22, 23, and 26, the liquid crystal shutters 24 and 27, the half mirror 25, and the television camera 40. .

Next, the operation will be described. The television camera 40 is supplied with a pulsed drive signal necessary for driving the television camera 40 as a three-dimensional imaging device of the television camera. In addition, the driving pulses, field pulses, and synchronization signals of the television camera output from the synchronization signal generator 4 are in synchronism with each other, and pulses necessary for synchronization from the television camera are synchronized with the pulses other than the three-dimensional imaging device of the television camera. To the synchronization signal generator (4). Light from a subject incident through the mirrors 22 and 23 and the liquid crystal shutter 24 passes through the half mirror 25 and is then imaged on the photoelectric conversion element of the image pickup device of the television camera 40. The light from the subject incident through the mirror 26 and the liquid crystal shutter 27 is folded by 90 degrees by the half mirror 25 and then imaged on the photoelectric conversion element of the image pickup device of the television camera 40. The optical axes of the optical path system 1 and the optical path system 2 are arranged so as to maintain an arbitrary angle θ (not shown) with respect to the same subject (the optical path systems 1 and 2 are respectively the right eye and the left eye of the human being). Corresponds to the eyes).

The optical shutter used in the present invention uses liquid crystal shutters that can control light interruption by voltage, have a sufficiently fast response speed with respect to the field scan frequency of a television camera, and have a long service life. The optical shutter may use an optical shutter having substantially the same configuration as that described in FIG. 6, and therefore the operation is also the same. Therefore, the configuration and operation thereof are simplified.

The liquid crystal shutters 24 and 27 are composed of components of the deflection plates 10 and 11, the liquid crystal 12, and the transparent electrodes 13 and 14 shown in FIG. Here, the liquid crystal shutters 24 and 27 are controlled by driving pulses supplied from the liquid crystal shutter driving circuit. As described above with reference to FIGS. 4 and 6, the liquid crystal shutter is described as light passing through when the field pulses supplied to the AND circuits 16 and 17 constituting the liquid crystal shutter driving circuit are at a low level. The field pulse is a signal in which the first field is high level and the second field is low level. Therefore, in the liquid crystal shutter, the liquid crystal shutter 27 shown in FIG. 1 transmits light in the first field, and the liquid crystal shutter 24 transmits light in the second field. Therefore, in the first field, the optical signal on the subject passing through the second optical path system is incident on the imaging device, and in the second field, the optical signal of the subject passing on the first optical path system is incident on the imaging device.

The image pickup device basically receives the optical signal from the subject over one field period or one frame period in the photoelectric conversion element, and accumulates (accumulates) the signal charges obtained by photoelectric conversion over one field period or one frame period. The accumulated signal charges are read out. For this reason, with respect to the optical signal incident on the imaging surface, the output signal has a delay time of one field period.

By the way, when the television camera 40 uses an image pickup device of a line sequential scanning method, for example, an image pickup tube or an X-Y matrix image pickup device (MOS type image pickup device), a three-dimensional image pickup signal cannot be obtained. The reason is explained using FIG. 4A schematically shows the state of the scanning field of the television camera and the liquid crystal shutter, and the potential of the point A of the imaging surface (photoelectric conversion element) of the image pickup device of the linear sequential scanning method, and b is the image pickup by the linear sequential scanning method. The imaging surface of the device is shown. In the first field, the optical signal from the subject image passing through the second optical path meter (liquid crystal shutter 27) is incident on the image pickup device, and in the second field, the subject image passed through the first optical path meter (liquid crystal shutter 24). The optical signal from is incident on the image pickup device. For convenience of explanation, the optical signal passing through the first optical system is R, and the optical signal passing through the second optical system is L. FIG. As an image pickup device, an image pickup tube that is an image pickup device of a line-sequential scanning method will be described as an example. The potential at point A of the imaging surface of the imaging tube gradually changes with time as shown in FIG. 4A due to accumulation of signal charges. When the predetermined scan timing comes, the signal charge at point A is read. However, at this time, in the signal charge generated at point A, as is apparent from FIG. 4A, the signal charge generated by the component SR of the signal charge generated by the light passing through the first optical path and the light passing through the second optical path ( SL) is mixed. In other words, since the light from the two optical paths is mixed and becomes equal to the incident on the image pickup device, only a blurry video signal is obtained from the television camera 40, and a three-dimensional image pickup signal cannot be obtained. Therefore, in this embodiment, the image pickup device used for the television camera 40 has at least a photoelectric conversion element and a vertical transfer end, or when the photoelectric conversion element also serves as a vertical transfer end, A structure having a storage unit for signal charge on an extension is used. The accumulation time of the signal charges to each photoelectric conversion element of the image pickup device is equal to or less than one field syringe, and a subject image from two optical path systems incident on the image pickup device is vertically transferred from the photoelectric conversion device of the image pickup device having the above-described configuration. The timing is similarly matched to the timing at which the signal charge is transmitted to the stage, and the optical shutter is used to alternate between fields.

As a specific example of the imaging device of the television camera which can be used for this invention, an interline transfer type charge coupling element (hereinafter abbreviated as IL-CCD), frame transfer type charge coupling element (hereinafter abbreviated as FI-CCD) or frame interline There is a transfer type charge coupling device (hereinafter abbreviated as FIT-CCD). Here, the case where IL-CCD is used as an imaging element is demonstrated. 2A is a schematic configuration diagram of an interline transfer type charge coupling device (IL-CCD) used in a three-dimensional imaging device according to an embodiment of the present invention. Since the IL-CCD is known, the configuration and operation thereof will be described here briefly. The IL-CCD is composed of a light receiving unit A and a horizontal transmission unit B as shown in FIG. 2A. 41 is a semiconductor substrate, and the light receiving portion A includes photoelectric conversion elements (light receiving elements) 42 and 42 'in a two-dimensional array, a gate 44 for reading out signal charges accumulated in these photoelectric conversion elements, and And a vertical transfer stage 43 composed of a CCD for vertically transferring the signal charges read out using the gate, and portions other than the photoelectric conversion elements 42 and 42 'are shielded by an alumina mask (not shown). have. The photoelectric conversion elements are separated by the channel stopper 45 together with the horizontal and vertical directions. In addition, an overflow drain (not shown) and an overflow control gate (not shown) are disposed in the vicinity of the photoelectric conversion element. The vertical transfer stage 43 is made of polysilicon electrodes øV1, øV2, øV3, and øV4 that are continuous in the horizontal direction and is connected every four horizontal lines in the vertical direction. The horizontal transfer unit B is composed of a horizontal transfer stage 46 consisting of a CCD and a signal charge detector 47, and the horizontal transfer stage 46 consists of transfer electrodes øH1, øH2, and øH3. The electrodes are connected to each other. The horizontal transmitter 46 transmits the signal charges transmitted from the vertical transmitters in the direction of the signal charge detector 47. The signal charge detector 47 is composed of a known floating diffusion amplifier, and converts the signal charge into a signal voltage.

Next, the operation will be briefly described. The signal charge accumulated by photoelectric conversion in the photoelectric conversion elements 42 and 42 'is applied to the signal readout pulse (øCH) superimposed on øV1 and øV3 among the vertical transfer pulses (øV1 to øV4) applied to the vertical transfer gate during the vertical retrace period. By this, it is transmitted from the photoelectric conversion elements 42 and 42 'to the vertical transfer end 43. At this time, when the signal readout pulse øCH is applied to øV1, only the signal charges accumulated in the photoelectric conversion element 42 are transferred to the potential well under the øV1 electrode. When the signal readout pulse øCH is applied to øV3, the photoelectric conversion element 42 is applied. Only the signal charges accumulated at ′) are transferred to the potential well under the? V3 electrode.

In this way, the signal charges accumulated in the plurality of photoelectric conversion elements 42 and 42 'arranged in two dimensions are transmitted to the vertical transfer stage 43 while the signal readout pulse? CH is applied. Therefore, if the signal reading pulses (øCH) are alternately alternated between øV1 and øV3 every other field, the IL-CCD performs frame accumulation operation because signals are read out every frame.

The signal charge transferred from the photoelectric conversion elements 42 and 42 'under the electrode of øV1 or øV3 of the vertical transfer stage 43 is one horizontal line per horizontal scanning period by the vertical transfer pulses (øV1, øV2, øV3, øV4). Awareness is transmitted and transmitted under the corresponding horizontal transfer electrode of the horizontal transfer stage 46. When the signal readout pulses? CH are applied to both? V1 and? V3 at substantially the same time within one field period, the signal charge accumulated in the photoelectric conversion element 42 is transferred to the potential well under the? V1 electrode, and the photoelectric conversion element 42 ' The accumulated signal charges are transferred to the potential well under the? V3 electrode, and each photoelectric conversion element reads a signal for each field so that the IL-CCD performs the field accumulation operation. At this time, the signal charges transferred from the photoelectric conversion elements 42 and 42 'under the electrodes of the? V1 and? V3 of the vertical transfer stage 43 are L in the first field and M in the second field and are adjacent to the vertical direction. After the signal charges from the device are mixed inside the vertical transfer stage, the horizontal transfer stage 46 transmits one horizontal line for each horizontal scan by the vertical transfer pulses øV1, øV2, øV3, and øV4. Is transmitted under a horizontal transfer electrode. The signal charge transmitted under the horizontal transfer electrode is transmitted to the signal charge detector 47 arranged in the horizontal direction by the high-speed horizontal transfer pulses øH1, øH2, and øH3, and converted into a voltage signal and output as a video signal from the image pickup device. do.

Next, the signal reading timing of the IL-CCD, the driving timing of the liquid crystal shutter, and the potential change of the z point of the photoelectric conversion element shown in FIG. 2A in the three-dimensional imaging device according to the present invention are shown in FIG. 2B. Pulse (VBLK) indicating the vertical retrace period in FIG. 2B, field pulses output from the synchronization signal generator 4 in FIG. 1, signal readout timing of IL-CCD, drive timing of liquid crystal shutter, z point of the photoelectric conversion element. Indicates a potential change, and an image pickup device output signal. The signal reading (transmission of signal charges) from the photoelectric conversion element to the vertical transfer end is performed in the vertical retrace period, and the switching of the liquid crystal shutter is approximately equal to the read timing of the signal from the photoelectric conversion element to the vertical transfer end. have. The switching timing of the field pulses also approximately coincides with the signal readout timing from the photoelectric conversion element to the vertical transfer stage. When the image pickup device and the liquid crystal shutter are driven at the timing, the optical signal on the subject passing through the second optical path is incident on the image pickup device in the first field, and the optical signal on the subject passing through the first optical path in the second field. Incident on the image pickup device. At this time, the potential of the z point on the image pickup surface of the scratch element gradually changes with time as shown in FIG. 2B, and when a predetermined timing (a signal readout pulse is applied from the photoelectric conversion element to the vertical transfer stage) is reached. The signal charge of the point is transmitted to the vertical transmission stage.

At this time, as is apparent from the second road, the signal charges obtained from the z point are only signal charges generated by light passing through the first optical path or only signal charges generated by light passing through the second optical path. In other words, light from two optical paths is mixed with each pixel of the photoelectric conversion element so as not to enter the image pickup device. By supporting the above-described configuration and driving timing, the image of the subject is picked up. In the first field from the television camera 40 shown in FIG. 1, the video signal of the subject image transmitted through the optical path system 1 is the second field. In this case, the video signals on the subject passing through the optical path system 2 are alternately outputted to obtain a three-dimensional video signal. In this embodiment, the signal charges of all the photoelectric conversion elements are transferred (read) to the vertical transfer stage, and then the signal charges from adjacent photoelectric conversion elements are mixed and transferred in the vertical transfer stage, and the image signal of the field accumulation is transferred from the image pickup element. The case of obtaining was demonstrated.

A second embodiment according to the present invention will be described with reference to FIG. In the IL-CCD, it is possible to obtain a field accumulation image signal without mixing the signal charges of two adjacent photoelectric conversion elements as described above. The principle is explained using FIGS. 2A and 3B. Pulse VBLK showing the vertical retrace period in FIG. 3A, field pulses output from the synchronization signal generator 4 in FIG. 1, signal readout timing of IL-CCD, drive timing of the liquid crystal shutter, z point of the photoelectric conversion element. Indicates a potential change, and an image pickup device output signal.

Next, the operation will be described. In the first field, a signal read pulse (? CH) is applied to? V3 to transfer the signal charge generated in the photoelectric conversion element 42 'to the vertical transfer stage, and a high speed transfer pulse (? V1 to? V4) is added to the vertical transfer pulse (? V1 to? V4). After transmitting at high speed by øVF) and discharging it from the horizontal transfer stage, a signal readout pulse (øCH) is applied to øV1 to transfer the signal charges generated in the photoelectric conversion element 42 to the vertical transfer stage 43. The transmission pulses øV1 to øV4 transmit one horizontal line every one horizontal scanning period, and are transferred under the corresponding horizontal transfer electrode of the horizontal transfer stage 46 to perform horizontal transfer. In the second field, a signal readout pulse (øCH) is applied to øV1 to transfer the signal charges generated by the photoelectric conversion element 42 to the vertical transfer stage 43, and high-speed transfer added to the vertical transfer pulses øV1 to øV14. After transmitting at high speed by the pulse øVF and discharging from the horizontal transfer stage, the signal read pulse øCH is applied to øV3 to transfer the signal charge generated in the photoelectric conversion element 42 'to the vertical transfer stage. The vertical transfer pulses? V1 to? V4 transmit one horizontal line every one horizontal scan period, and are transferred under the corresponding horizontal transfer electrode of the horizontal transfer stage 46 to perform horizontal transfer. By the above operation, a video signal of field accumulation can be obtained. As is apparent from FIG. 3A, the discharge of unnecessary signal charges and the transfer of signal charges from the photoelectric conversion element to the vertical transfer stage are performed in the vertical retrace period. In this way, the light from the two optical paths is not mixed with each pixel of the photoelectric conversion element and irradiated to the image pickup device, and the optical path system 1 is provided in the first field from the television camera 40 shown in FIG. The video signal on the subject having passed through is alternately outputted by the image signal on the subject having passed through the optical path system 2 in the second field, thereby obtaining a three-dimensional video signal.

In the IL-CCD, the accumulation period of the signal charges to the photoelectric conversion element can be made shorter than one field period. The purpose of shortening the accumulation time of the signal charge is to improve the dynamic resolution of the video signal. The imaging device obtains a video signal by accumulating (accumulating) signal charges generated by an optical signal incident on the photoelectric conversion device. Therefore, if the subject image moves during the period in which signal charges are accumulated, the resolution of the video signal (this is called dynamic resolution) deteriorates. In order to improve the dynamic resolution, it is necessary to shorten the integration time of signal charges. The present invention is also effective when the integration (accumulation) time of signal charges is shortened.

The principle is explained below using FIGS. 2A and 3B. Pulse (VBLK) indicating the vertical retrace period in FIG. 3b, field pulse output from the synchronization signal generator 4 in FIG. 1, signal readout timing of IL-CCD, drive timing of liquid crystal shutter, potential of overflow control gate , The potential change at the z point of the photoelectric conversion element, and the image pickup device output signal. The overflow drain (hereinafter referred to as OFD) is installed to prevent blooming peculiar to solid-state imaging devices such as IL-CCD, and the amount of charge that can accumulate in the photoelectric conversion elements is controlled by an overflow control gate (Over Flow Drain). The control gate (hereinafter referred to as OFCG) is set, and when signal charges exceeding the set value are generated, unnecessary signal charges are absorbed by the OFD beyond the OFCG and discharged from the image pickup device.

Therefore, if the potential barrier of the OFCG is lowered (that is, the applied voltage to the OFCG is high) while the optical signal from the subject is incident on the photoelectric conversion element (in the middle of the vertical retrace period), it is accumulated in the photoelectric conversion element. Signal charge is discharged to OFD. Therefore, the potential of the photoelectric conversion element Z point is as shown in FIG. 3B. By the above operation, a video signal having an accumulation time shorter than the field period can be obtained. In this way, the light from the two optical paths is not mixed with each pixel of the photoelectric conversion element and irradiated to the image pickup device, and the optical path system 1 is connected to the first field from the television camera 40 shown in FIG. In the second field, the video signal transmitted by the image transmitted on the subject is alternately outputted by the image signal transmitted through the optical path system 2, thereby obtaining a three-dimensional video signal.

In the present embodiment, the case of the lateral OFD in which OFCG and OFD are arranged in the vicinity of the photoelectric conversion element has been described. However, the present invention can also be applied to the vertical OFD in which the OFD is disposed in the inward direction of the imaging device. In addition, even when the accumulation time is controlled using the frame interline transfer solid-state image pickup device, the operation principle described in FIG. 3B can be applied as it is. Since the details of the frame interline transmission solid-state image pickup device are described in Japanese Patent Laid-Open No. 55-52675, the description thereof is omitted here, but basically, the vertical transmission stage of the above-described A vertical transfer stage for storage is arranged on an extension, and the object thereof is a smear generated in the vertical direction by transferring signal charges obtained from the light-receiving unit to the vertical transfer stage for storage at high speed, and then sequentially reading them. It is possible to reduce the occurrence of smear and to set the exposure time of the photoelectric conversion element arbitrarily. The setting of the exposure time of the photoelectric conversion element arbitrarily is the same as that described in FIG. 3B as an example of the control of the exposure time (accumulation time) using the interline type solid state image pickup device. However, in FIG. 3B, the switching of the optical path system incident on the television camera is switched by roughly coinciding with the timing of pushing the signal charge from the photoelectric conversion element into the vertical transfer stage. However, as apparent from Fig. 3b, for example, the optical path system may be switched by the liquid crystal shutter so that the pulse phase voltage applied to the OFCG is approximately coincided with the input timing. The subject image from each optical path system incident on the photoelectric conversion element may be approximately equal to the timing at which the read pulse is applied from the timing at which the pulse phase voltage applied to the OFCG is applied. In addition, it is apparent that when the accumulation period of the signal charges accumulated in the photoelectric conversion element is shorter than one field period, it is not necessary to make the time from two optical path systems incident on the television camera the same. That is, the subject image from the optical path system irradiated to the photoelectric conversion element of the solid state imaging element may be approximately equal to the signal accumulation time or may include the signal accumulation time.

As described above, the present invention synchronizes the subject image of two optical path systems with the field scan (timing of transferring signal charge from the photoelectric conversion element to the vertical transfer cup) of the imaging device of the television camera, and alternately selects The imaging is performed in three dimensions using a single television camera. Although the timing shown in Figs. 2 and 3 is used in this embodiment, the read timing of the signal charge and the switching timing of the liquid crystal shutter may be within the vertical retrace period. In addition, the relative misalignment between the read timing of the signal charge and the switching timing of the liquid crystal shutter can be tolerated practically as long as it is about the vertical retrace period. In the case of the present embodiment, since the three-dimensional image display apparatus is exactly the same as that described in FIG. 4, the description thereof is omitted. In addition, the synchronization signal generator 4 of this embodiment has a part which can be shared with the pulse generator of the television camera 40, and in particular, the image pickup device driving signal is transformed into a configuration that is shared with the internal signal of the television camera. It is possible.

[Industry availability]

As described above, when the present invention is used, the three-dimensional imaging apparatus can be realized by adding the optical path switching optical system and the control circuit to one unit, so that the imaging apparatus itself becomes inexpensive. In addition, since it is not necessary to precisely adjust the angle between the subject and the television camera in order to capture the three-dimensional image on the subject with one camera, the operation of adjusting the angle of view and focus is extremely simple. Therefore, not only anyone can image a three-dimensional image but also mobility is improved.

Claims (7)

The signal charge accumulated in the photoelectric conversion elements 42 and 42 'is formed by at least the photoelectric conversion elements 42 and 42' and the vertical transfer stage 43 corresponding to the photoelectric conversion elements 42 and 42 '. A television camera 40 having an image pickup device for reading out the signal charges at least once in one field by simultaneously transmitting to the vertical transfer stage 43; Two optical path systems that are alternately switched for each field to be imaged by substantially matching transmission timing for transmitting signal charges from the photoelectric conversion elements 42 and 42 'to the vertical transfer stage 43; A plurality of shutters 24 disposed in each of the two optical path systems to block light, and alternately selecting a subject image obtained through the plurality of optical path systems in synchronization with the field scan operation of the television camera 40; , 27) and; Control device for driving the shutter (24, 27) for blocking or transmitting light in synchronization with the transmission timing for transmitting the signal charge from the photoelectric conversion elements (42, 42 ') to the vertical transfer stage (43) Three-dimensional imaging device consisting of. The photographic conversion of the subject image according to claim 1, wherein when photographing the subject images from the two optical path systems by switching between fields alternately, the subject images for which the accumulation period of signal charges to the photoelectric conversion elements 42 and 42 'are selected. The photoelectric conversion elements 42 and 42 'are irradiated to the photoelectric conversion elements 42 and 42' with the same or shorter duration of the irradiation with the elements 42 and 42 ', and the accumulation period of the signal charges to the photoelectric conversion elements 42 and 42' is selected. 3D imaging device, characterized in that within the period. 2. The image pickup device according to claim 1, wherein the image pickup device includes a storage unit for signal charges on an extension of the transfer direction of each vertical transfer stage (43) when the photoelectric conversion elements (42, 42 ') also serve as the vertical transfer stage (43). And a three-dimensional imaging device. 2. The signal charge of the photoelectric conversion elements (42, 42 ') is transferred to the vertical transfer stage (43), and the signals of two photoelectric conversion elements (42, 42') adjacent to each other in the vertical direction. 3D imaging apparatus characterized by outputting after mixing electric charges and performing vertical transfer and horizontal transfer. The photoelectric conversion elements (42,42 ') according to claim 1, wherein the image pickup device previously stores the signal charges accumulated in the photoelectric conversion elements (42, 42') by irradiation on a subject, and the signal charges obtained by photoelectric conversion before a predetermined time. And the vertical transfer stage 43 are removed so that the irradiation of the subject onto the photoelectric conversion elements 42 and 42 'is equivalently controlled within one field period. The optical path system according to claim 1, wherein the optical path system comprises a plurality of mirrors (22, 23, 26), and shutters (24, 27) for blocking light, and the image of the subject obtained through the plurality of optical path systems (TV cameras). And the shutters (24, 27) are alternately selected in synchronization with the field scan of (40). The three-dimensional imaging device according to claim 1, wherein the two optical path systems are arranged in front of the television camera.

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